Improvement methods of bending accuracy for 6000 series aluminum alloy extruded shapes in press bending

In this paper, the results of an experimental study on improvement methods of bending accuracy of 6000 series aluminum alloy hollow square cross-section extruded shapes in press bending are presented. Cross-sectional distortion with buckling is a problem encountered during bending, because it reduces the bending accuracy of products. First, a restraining method of buckling by means of an internal mandrel has been examined. Second, some methods of restraining localized deformation by means of a variable die opening system and counterpressure have been investigated. Experimental results have revealed that the formability of an aluminum alloy cross-sectional shape is improved by restraint buckling and local deformation.